Here is my problem. I wanted to reset the os to factory settings but i mistakenly erased/cleared the hard disk which the OS is in. I failed to make a copy or back-up. So, i dont have an existing OS running.

I tried to reinstall lion via the internet recovery but i end up with an error that the os is not available. i do have an apple ID but i was not able to download an os beforehand. so, i dont think i can use this option.

Im left with the recovery utilities. whenever i try to boot, i can only see the recovery HD in the startup screen. i believe that the os installer and the hardisk icons should be seen also if i insert the bootable usb and the empty hardisk too(mackintosh HD)

I downloaded the DMG file of Mac OS Yosemite from getintopc.com it was noted the the file is for 32 and 64 bit windows. does it mean that the os is for windows use only? like the hackintosh or dual boot system. do you happen to know any reliable site where i can download a legit DMG file or what specific DMG file do i need to download? the retail one? the one from app store? there are many in the torrent sites. i cant figure what to download.

I tried to make a bootable usb using transmac in my Windows xp laptop but will not boot when i plug it in my MBA. also, it took me 6-8 hours just to write the os in the disk. any other alternative app? or maybe my DMG file is corrupted.

can i use ISO file of the Yosemite to boot from the macbook?

i just want to make a usb bootable mac os x(any os) using my windows xp since im not able to use my MBA

how to properly prepare my hard disk for usb bootable mac os install? do i need to 2 partition? i cant seem to partition it properly.

When you erased the partition did you format it is a Apple Extended Format (Journalled) or something else (like FAT32, for instance)?

Click to expand...

I think OP is in a bit of a pickle. It sounds like he booted to recovery then erased Macintosh HD. So to reinstall he needs to supply an AppleID that has a Lion purchase attached to it. Not having such an AppleID, he is stuck.

Then the machine is an older model that does not support Internet recovery. So somehow he is going to need to setup a USB installer on another Mac.

Here's one more example of not having a "second completely bootable backup" around. Without a second source from which to boot to the finder, the OP is flopping around like a fish out of water.

If the OP had had a bootable cloned drive, he'd be up-and-running now.

OP:
I suggest you "go to the torrents" to find the OS you need to get running again.
Do you have access to another computer, even a PC?

Alternative course of action:
I would suggest you buy two things:
1. An external USB DVD/CD drive, any will do (doesn't have to be "Apple-labeled"). Should run you about $25.
2. A copy of OS 10.8 "Mountain Lion" from ebay -- should run about $20

This will give you a bootable OS and the means to mount and install it.

Connect the DVD drive, put the install DVD into it.
REboot and hold down the option key until the startup manager appears.
Select the DVD and try booting from it.
If you get a good boot and get to the installer, run it...

Mark, did you try simply re-installing the OS while booted from the recovery partition? If you boot holding down command-r and select Re-Install OS X, you should be able to install the operating system without an external disk or ISO.

Thanks guys for all you help. I just went to a tech shop yesterday and have them install a mac os x for a fee ($25). i guess there was a mistake in making the bootable usb using my windows xp.

anyhow, I'm currently running Yosemite 10.10.1 right now and it works fine but I'm starting to have issue running it. the yosmite makes my mac slow and consumes a lot of RAM. i did all the tips and tricks in making it faster (did not try the pram and dmc reset since its a fresh install, do i have to do this?) and ram clearing but it still lags even just opening 2-3 apps (safari, utorrent, and activity monitor).

i was searching the net for the best mac os to run my MBA 2009 13" 1.86ghz, 2GB RAM. do you happen to know what os best fits my mac. making it run smooth and fast.

i primarily use my mac for simple basic task like MS word, surfing the net, opening PDF files and images, Skype and movies. thats practically my everyday tasks as i have an iPad and iPhone to help ease the use of my MBA

i tried your advice JohnDS but my MBA still lags quite often. i just open safari (2-4tabs, 1tab uses flash), skype and activity monitor. fans are noisy too.. i think the yosemite is too much for my mac. is mavericks way better in handling MBA 2009? although my memory pressure is at the green level. the running of my mac is just too laggy. was hoping to use it a bit smoother. i dont expect to be really fas, just average maybe.

You might want uninstall Antivirus software you have installed, it's using quite a lot of RAM and processor time. If you regularly send files to Windows users then it might be worth it to keep using it but otherwise it won't give you any benefits as there is currently no viruses on OS X.

If that doesn't help next step is to install EtreCheck which collects diagnostic information about your Mac.

You might want uninstall Antivirus software you have installed, it's using quite a lot of RAM and processor time. If you regularly send files to Windows users then it might be worth it to keep using it but otherwise it won't give you any benefits as there is currently no viruses on OS X.

If that doesn't help next step is to install EtreCheck which collects diagnostic information about your Mac.

Click to expand...

I'm using bitdefender as my antivirus. it keeps on updating on background. i tried to turn off the auto-pilot option. my mac does seems a bit faster and my mac does not heat up that much. going to observe this. also, i switched back to safari instead of firefox. I'm sure it eats more ram than safari.

I'm using bitdefender as my antivirus. it keeps on updating on background. i tried to turn off the auto-pilot option. my mac does seems a bit faster and my mac does not heat up that much. going to observe this. also, i switched back to safari instead of firefox. I'm sure it eats more ram than safari.

Click to expand...

Yes, use Safari. Native OS X apps usually run better that 3rd party apps, especially on low RAM machines.

Get rid of the antivirus all together. It is not necessary on OS X, and if you intend to send files to a Windows machine, let them deal with it. Generally they run antivirus software anyway, so it should be caught on their end. (I hate that logic, but you have to do what you can to make your machine pleasant to use.)

If that's a Core2Duo Air, you might look into CoolBook. I don't know if it works with Yosemite though. Or SMCFanControl.

I have an old Mac Mini that I'm still running Mavericks on because it runs better that Yosemite or El Cap. However, not ever having "purchased" Mavericks from the Mac App Store, the only place your going to find it is from an illegitimate source. Apple still displays the SHA1 hash on the Mavericks website (I think), so be sure you compare your copies SHA1 to the official to make sure you got an clean copy.

If you decide to downgrade to Mavericks, make a Mavericks USB installer in Yosemite before you wipe the hard drive. DiskMakerX works great for this.

Yes, use Safari. Native OS X apps usually run better that 3rd party apps, especially on low RAM machines.

Get rid of the antivirus all together. It is not necessary on OS X, and if you intend to send files to a Windows machine, let them deal with it. Generally they run antivirus software anyway, so it should be caught on their end. (I hate that logic, but you have to do what you can to make your machine pleasant to use.)

If that's a Core2Duo Air, you might look into CoolBook. I don't know if it works with Yosemite though. Or SMCFanControl.

I have an old Mac Mini that I'm still running Mavericks on because it runs better that Yosemite or El Cap. However, not ever having "purchased" Mavericks from the Mac App Store, the only place your going to find it is from an illegitimate source. Apple still displays the SHA1 hash on the Mavericks website (I think), so be sure you compare your copies SHA1 to the official to make sure you got an clean copy.

If you decide to downgrade to Mavericks, make a Mavericks USB installer in Yosemite before you wipe the hard drive. DiskMakerX works great for this.

I agree with others. That antivirus is using way too much of your already-limited resources. Even if it was worthwhile to use, the constant background activity makes it even worse on your low RAM system. Like many other Mac users, you too can be successful by choosing to ignore the need to have active antivirus protection.

I agree with others. That antivirus is using way too much of your already-limited resources. Even if it was worthwhile to use, the constant background activity makes it even worse on your low RAM system. Like many other Mac users, you too can be successful by choosing to ignore the need to have active antivirus protection.

Click to expand...

thank you for your reply.

i would like to ask for you opinion with regard to the best mac os for my macbook air 2009 1.86ghz 2gb ram.

i can only run at least 2 apps at a time. going more than that plus using flash will heat up my mac and the fan is screaming. i make sure my mac is well ventilated and placed on a desk. but the fan is running so fast. it gets hot I'm worried its gonna destroy its internal components.

MacRumors attracts a broad audience
of both consumers and professionals interested in
the latest technologies and products. We also boast an active community focused on
purchasing decisions and technical aspects of the iPhone, iPod, iPad, and Mac platforms.